The school bus manufacturing industry fabricates bus bodies using a “stick framing” process. That process is heavily labor- and part-intensive. Actual fabrication process sheets call for specific operations too numerous to mention here; hence only a general overview of the process will be given as background.
A number of bows are fabricated and installed at intervals along the length of the bus body. Fixtures for locating and holding the bows are placed on seat rails that run along opposite sides of the floor. The bows are manually placed in the fixtures and preliminarily fastened in place. Drip rails and bow spacers are located to the bows using other fixtures. The preliminarily assembled parts are checked for squareness and fit, adjusted as needed, and checked again before parts are finally joined together using fasteners and welding. Trimming of certain parts may then be performed.
At some point in the process, windows are installed between bows, the body sides are closed by exterior side panels, and the open top of the body is capped by fitting the roof onto the bows and fastening it in place.
Certain bus specifications call for reinforcement of the bows in various ways, adding more steps and parts to the fabrication process.
As commercial vehicles, busses are typically subjected to regular daily use. Some school buses operate in rural areas where roads are often unimproved. Some busses operate under extreme weather conditions. Consequently, the recognition that busses must provide a reasonable service life in these circumstances calls for them to be sturdily built.